(CNN)"I was surrounded by cameramen, all on their knees like proposing Victorian swains, shooting upwards to make my skirt look even shorter. I had no idea this was going to happen -- this was publicity that I certainly had not planned." Model Jean Shrimpton.

On a sultry spring day in 1965, silence descended on the packed crowd gathered at Australia's biggest sporting event.

All eyes were on British supermodel Jean Shrimpton as she arrived at the prestigious Melbourne Cup Carnival -- or more accurately, all attention was focused on the 22-year-old's legs.

"The most beautiful girl in the world" had stepped out at Flemington Racecourse wearing a minidress five inches above her knees, with no hat, stockings or gloves.

In an era when women didn't leave the house without wearing a hat, it was an outfit which both scandalized the nation and sparked a fashion revolution which would define the Swinging Sixties.

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The iconic image of Shrimpton in "that dress" has gained almost mythical status in the history of a horse race now worth $6.2 million in prize money.

Known as "The race that stops a nation," it is one of the richest thoroughbred competitions in the world, and is so revered in its home state of Victoria that its annual date -- the first Tuesday in November -- has been made a public holiday.

But in 1965 it was Shrimpton's legs which famously stopped the country in its tracks.

"She was one of the world's first supermodels and her visit was highly anticipated -- everyone was expecting this beautiful hat and accessories," Victoria Racing Club Art and Heritage curator Penny Tripp told CNN.

"When Jean came marching through the members' lounge two hours late with her boyfriend of the time -- Hollywood actor Terence Stamp -- in this casual dress, there was absolute silence."

The conservative country was rocked by the seemingly skimpy outfit and, for the first time since the inaugural race in 1861, the winning horse was knocked off newspaper front pages -- in favor of Shrimpton's legs.

"There she was, the world's highest-paid model, snubbing the iron-clad conventions at fashionable Flemington in a dress five inches above the knee, NO hat, NO gloves, and NO stockings!" screamed Melbourne newspaper The Sun.

"The Shrimp," as she was known, had been employed by textile manufacturer DuPont de Nemours International to be a judge in the annual "Fashions on the Field" dress competition.

The face of "Swinging Sixties London" was flown to other side of the world to promote DuPont's new fabric, Orlon, during the four days of the Melbourne Cup Carnival -- Derby Day, Melbourne Cup, Oakes Day and Stakes Day.

Shrimpton was sent rolls of the material, designing her secret wardrobe with London dressmaker Colin Rolfe.

With limited fabric, Rolfe was forced to create the now-famously short dress. Though Shrimpton appeared undeterred by the length, telling Australian Women's Weekly magazine: "I always wear my day dresses above the knee."

DuPont quickly employed Melbourne milliner Adele Chapeaux to create a hat for Shrimpton's next appearances. The model complied -- for one day. By the end of the carnival she had converted back to her trademark stripped-back mod look.

"It had an enormous impact on the fashion world," Tripp said. "Shrimpton credits the arrival of the miniskirt to her wearing it at Derby Day, though it was probably London designer Mary Quant who invented it the year before.

"Regardless, it was very much the pivotal moment of the introduction of the miniskirt to an international stage."

Despite the scandal, Melbourne designers copied the fashion icon in droves. The following year, newspaper The Age reported: "Last year's controversial Miss Shrimpton would have passed unnoticed in the crowd this year. Anyone with hemlines below the knee looked very 'old hat.' "

Today, more than 350,000 people attend the Melbourne Cup Carnival, with 1,100 men and women taking part in last year's "Fashions on the Field" event.

Competitors are judged on their originality, accessories, understanding of current fashion trends and deportment, with prizes including a Lexus IS 250C F Sport convertible.

"I think to the rest of the world, the Melbourne Cup probably looks like one big party -- and that's exactly what it is," said Angela Menz, the 2011 fashion competition winner.

"Everyone makes an effort to dress up. But it's done in a very different way to say, Ascot in England, for example. The lifestyle in Australia is quite relaxed -- we don't have to wear gloves and jackets because it doesn't get that cold.

"By today's standards, Shrimpton's dress was actually quite long."

This year, Menz is predicting lots of tall hats, rather than traditional large brims. "Head wear has been getting quite sculptural, almost like a piece of art on the head," she said.

Since Shrimpton first graced Flemington, international celebrities have become a regular feature of the Melbourne Cup, with high-profile appearances from Britain's Princess Diana in 1985, Kate Bosworth in 2006 and fellow American actress Sarah Jessica Parker last year.

The Melbourne Cup is as much about its fashion stakes as its horses. But when it comes to groundbreaking outfits, no one has ever come close to "The Shrimp."